Gbm13 chord

The G-flat minor thirteenth chord (abbreviated Gbm13 chord) is a seven-note chord consisting of the notes G♭, B♭♭, D♭, F♭, A♭, C♭, and E♭. The chord is formed by adding a thirteenth to the G-flat minor eleventh chord.

In practice, the fifth (D♭) and eleventh (C♭) are often omitted from the Gbm13 chord to avoid a very dissonant sound, and because it's not always possible to play all notes simultaneously.